All fish / Osphronemidae

Roundtail Paradise Fish

Macropodus ocellatus

Also known as round tail paradise fish, roundtailed paradisefish, chinese paradise fish, macropodus chinensis, black paradise fish, korean paradise fish, チョウセンブナ, 圆尾斗鱼, 黑斗鱼

A sturdy labyrinth fish with a rounded tail, long fins and a brownish body marked with dark bars and a dark gill spot, with males turning almost black with blue edging when breeding. It is kept because it is very hardy, tolerates cool unheated rooms and shows interesting bubble nest behaviour.

Care at a glance

Care level

Easy

Temperament

Semi

Adult size

6 cm

Temperature

10 to 25 °C

pH

6 to 8

Smallest tank

60 litres

Keep as

One male with one or two females, or a single fish

Diet

Omnivore: flakes, small pellets, frozen bloodworm, brine shrimp and daphnia

Swims

Top of the tank

Lifespan

5 to 8 years

Water

Freshwater

Wild range

Eastern China, Korea, Japan (introduced), Taiwan and the Amur basin

Breeding

Males build a bubble nest at the surface, often among floating plants, and guard the eggs and fry after spawning. Breeding is easy, ideally after a cool winter period, but the female should be removed once spawning is over.

Good to know

Males are territorial and will fight each other, and may pick on slow or long-finned tankmates. It does best in cool water and does not need tropical heating; it can be invasive outside its native range.